Dustproof static eliminator



June 16, 1964 H. SCHWERINER 3,137,806

DUSTPROOF STATIC ELIMINATOR Filed Nov. 22, 1960 INVENTOR ff //ar0/a5Jcweraher ATTORNEYS United States Patent 3,137,806 DUSTPRUOF STATICELIMINATOR Harold Schweriner, Lansdale, Pa, assignor, by mesneassignments, to The Sirnco Company, Inc., Lansdale, Pa., a corporationof Pennsylvania Filed Nov. 22, 1960, Ser. No. 71,090 8 Claims. (Cl.317--2) This invention relates to static eliminators and to a method ofassembling such elirninators. More particularly, it relates to dustproofextended-range air-ionizing static eliminators and to their assembly.

The need for eliminating static charges in the course of manipulatingnon-conductive materials is so well recognized as not to warrant furtherdiscussion herein. Static eliminators are utilized in industries whichinclude, inter alia, printing, textile processing, paper converting andplastic manufacture.

A common type of static eliminator utilizes a field of ionized air todissipate the static charge on any object passing therethrough. Thefield is created by impressing a high voltage, which may be of changingpolarity, across an air gapusually between a needle or point and a flatsurface placed in proximity thereto. Such a prior art device is thatshown in US. Patent No. 2,163,294. As shown therein, it is customary touse a row of needles having a common source of voltage located in fixedrelationship to a surface or plate. It is in the gap between the needlesand the plate that a field of ionized air exists when a high voltageexists on one with respect to the other.

In dusty atmospheres, dirt and dust accumulate in the space between theneedles and the plate. When the gap is bridged, a short circuit resultsand the device is rendered inoperative. Therefore, periodic cleaning ofthese prior art devices was essential.

Furthermore, in the assembly and construction of the prior art devices,elaborate techniques were required to provide an array of needlesadapted to be kept in fixed relationship to the plate and to each other.Often the needles were soldered to a common conductive rod with the useof special tools, jigs and fittings.

Additionally, in prior art devices, the field of ionized air existedalmost entirely within the gap between the needle and conductive plate,spanning the linear distance therebetween.

Accordingly, it is an object of the present invention to provide astatic eliminator which can be operated in a dusty atmosphere withoutany possibility of a short circuit developing due to accumulation ofdust or other foreign matter.

It is an additional object of the invention to provide a staticeliminator capable of creating an arcuate extended field of ionized air.

Still another object of the invention is to provide a method ofassembling a static eliminator having a plurality of needles wherein theneedles may be quickly assembled and retained in fixed relationship to aconductive surface.

The provision of an improved device of the character described that iseasily and economically produced, which is sturdy in construction, andwhich is highly efficient in operation is also an object of theinvention.

These and other objects of the invention will be apparent to thoseskilled in the art from the following detailed description of anembodiment thereof when read in conjunction with the accompanyingdrawing wherein:

FIGURE 1 represents a perspective view of an extended range dust-proofstatic eliminator embodying the invention as well as a diagrammaticrepresentation of a typical circuit used in connection therewith.

3,137,806 Patented June 16, 1964 "ice FIGURE 2 represents a sectionalview taken along lines 22 of FIGURE 1.

FIGURE 3 represents a partial sectional view taken along lines 33 ofFIGURE 1.

FIG. 4 represents an exploded view of the static eliminator shown inFIG. 1.

Referring now to the drawing, with particular reference to FIGURES 1 and4, the embodiment shown includes a non-conductive core A, which fitsinto a conductive housing B, a conductor C positioned within the core Ato which are afiixed a plurality of needles D. Also, as indicated inFIGURE 1, a source of high voltage, E, is provided.

The core A is generally rectangular in cross-section and is made of anon-conductive material, preferably a plastic such as, for example,polymers or copolymers of acrylic acid, condensation products of phenolsand aldehydes, aminoplastics, polymers of halogenated hydrocarbons,polyamide resins, polyester resins, epoxy resins and allyl resins. Asbest shown in FIG. 4, this core includes upper cars 10 and 11 having,respectively, upper faces 12 and 13. The core, being rectangular inshape, has sides 14 and a bottom 15 as well as ends 16 and 17. Aninternal longitudinal bore 18 is provided which extends from end 16toward end 17 and, as shown in FIGURE 3, terminates within the core somedistance from end 17. The cars 10 and 11 cooperate with shoulders 19 and20 to form slideways 21 and 22. Finally, the core is provided with alongitudinal slot 23 within which are a plurality of pin receivingapertures 24 extending from the bottom of the slot to the perimeter ofbore 18.

The conductive housing B is preferably made of a metal such as aluminum,brass, copper or steel. As shown in FIGURE 4, it includes flanges 30 and31, sides 32 anda bottom 33. Conductive binding posts 34 are secured tothe bottom 33 in a conventional manner as with machine screws 35. Thehousing is also drilled and tapped to receive and retain a set screw 36which is adapted to press against core A.

Conductor C is a conventional insulated wire which includes a conductivecore 40 and a plurality of insulating layers such as inner layer 41 andouter layer 42. The conductor should have a high dielectric breakdownrating, preferably on the order of 15,000 volts.

Needles D are all identical and includes a straight shank 45 and pointedends 46.

The method of assembling the device, which method is generic to anystatic eliminator comprising a non-conductive longitudinal corecontaining a wire with which one end of a plurality of needles must makeelectrical contact, the other end of said needles being in spacedrelationship to another conductor, may be as follows. Conductor C isinserted into the internal bore 18 of core A until it abuts end 17 asshown in FIGURE 3. No special preparation of the conductor is requiredsuch as stripping of insulation or the like. inserted in apertures 24and pressed down until their lower pointed ends 46 pierce insulatinglayers 41 and 42 and are fixedly embedded in core 40. Needles D thus arein electrical communication with core 40 while simultaneously preventingany motion of conductor C with respect to core A. The diameter ofapertures 24 is preferably very slightly larger than the diameter ofneedles D so as to give a tight and positive fit. When the assembly iscompleted, the upper points 46 of needles D should be substantiallylevel with faces 12 and 13 and not protrude beyond them. Because shanks45 are exposed to air within slot 23, an increased amount of air isionized.

Housing B is assembled by merely affixing the binding posts 34. As shownin FIGURE 2, the head of screw 35 is countersunk into the bottom 33 sothat it is flush therewith.

The static eliminator is thereafter assembled by sliding Thereafter,needles D are.

core A into housing B so that flanges 30 and 31 ride in slideways 21 and22. After the core A is fully encompassed in housing B it is securedthereto, for instance with set screw 36. p

In use the device is connected, as shown in FIGURE 1,

to a source of high voltage, E. This voltage source may be any AC. orDC. power unit producing a high voltage electromotive force in the rangeof from about 2,500 to above about 10,000 volts and preferably yieldinglow amperages on the order of a few milliarnperes. A unit designated asthe Simco Midget Power Pack, Model SR165S4, has been found quitesuitable although many other commercially available high voltage lowcurrent power sources may be equally satisfactory for this pur- 'pose. jThe high potential which, in effect, is applied from sides 32 to pointedends 46 causes a field of ionized air to exist which extends fromneedles D around faces 12 and 13 to sides 32 in an arcuate pattern. Thusa relatively extended field is available for use in commercialapplications. Because the faces 12 and 13 are flat and at right anglesto sides 32, there is no possibility of dust accumulation causing ashort circuit between needles and conductive sides.

It is thus seenthat the device and method illustrated and describedachieve the objects first stated above. It will be appreciated by thoseskilled in the art that the foregoing description merely illustrates theinvention and that the same should not serve to unnecessarily limit orrestrict it. Various modifications of the disclosed invention may bepracticed without departing from the spirit and scope of the same.

What is claimed is:

1. An extended range dustproof static eliminator comprising alongitudinally extending hollow conductive outside housing; alongitudinally extending non-conductive core mounted within said housingincluding ear portions which project outwardly of said housing and bendback to shield one facethereof; an insulated conductor includinginsulationand a conductive portion mounted longitudinally within saidcore; a plurality of radial apertures in said core extending from saidconductor to the exterior portion of said core which is between saidears; and a plurality of needles pointedat both ends mounted in andencapsulated by said apertures, ,each having one end in contact with theconductive portion of said conductor and one end projecting outwardlyfrom said aperture. t

2. The static eliminator of claim l wherein, further, said core includesa longitudinal groove between .said ears and said needles extend out ofsaid apertures into said groove. V

3. The static eliminator of claim 2 wherein said'housing is metallic andsaid core is made of an acrylicresin. I

4. An extended range dustproof static eliminator comprising a hollowbar-shaped conductive housing having a longitudinal slot in one facethereof; a non-conductive, generally rectangular core mounted withinsaid housing further including ear portions which extend outwardlythrough said slot in said housing and shield one face thereof; alongitudinal bore within said core extending from one end thereof towardthe other; a plurality of aligned apertures extending radially from saidbore to the exterior portion of said core between said cars; a wireincluding a conductor and a plurality of integral insulating layersmounted within said bore; and a plurality of needles mounted in saidapertures each piercing said insulating layers at one end to makeelectrical contact with said conductor and extending outwardly from saidapertures at the other end and being encapsulated thereby.

5. The static eliminator of claim 4 wherein further said core includes alongitudinal groove between said ears and said needles extend out ofsaid apertures into said groove.

6. The static eliminator of claim 5 which further includes binding postsaflixed to the exterior of said housing.

7. The static eliminator of claim'6 wherein said housing is metallic andsaid core is made of an acrylic resin.

8. An extended range dustproof static eliminator comprising alongitudinally extending, hollow, conductive outside housing; means forgrounding said housing; a longitudinally extending non-conductive coremounted within said housing and conforming to the internal configurationthereof, including integral ear portions which extend transverselybeyond the body of said core and shield one entire face of said housing;a longitudinally extending bore within said core adapted to receive alength of conventional insulated wire; a plurality of longitudinallyaligned apertures in said core along the length thereof, each connectingthe interior of said bore with aligned points on the surface of saidcore body intermediate said ear portions; an insulated wire adapted tobe connected to a source of high voltage having a conductive center andintegral insulation thereabout mounted within said bore; and a pluralityof needles encapsulated in said aligned apertures, each having one endpiercing said integral insulation and in electrical contact with saidconductive center and the other end exposed between said ear portions;whereby said needles simultaneously serve as discharge points and meansfor fixing said insulated wire and whereby, further, a field is providedwhich extends from said needles, around said ears to the exposed portionof said conductive housing.

References Cited in the file of this patent UNITED STATES PATENTS940,431 -Chapman Nov. 16, 1909 2,087,915 Kimball July 27, 1937 FOREIGNPATENTS i 295,321 Switzerland Mar. 1, 1954

1. AN EXTENDED RANGE DUSTPROOF STATIC ELIMINATOR COMPRISING ALONGITUDINALLY EXTENDING HOLLOW CONDUCTIVE OUTSIDE HOUSING; ALONGITUDINALLY EXTENDING NON-CONDUCTIVE CORE MOUNTED WITHIN SAID HOUSINGINCLUDING EAR PORTIONS WHICH PROJECT OUTWARDLY OF SAID HOUSING AND BENDBACK TO SHIELD ONE FACE THEREOF; AN INSULATED CONDUCTOR INCLUDINGINSULATION AND A CONDUCTIVE PORTION MOUNTED LONGITUDINALLY WITHIN SAIDCORE; A PLURALITY OF RADIAL APERTURES IN SAID CORE EXTENDING FROM SAIDCONDUCTOR TO THE EXTERIOR PORTION OF SAID CORE WHICH IS BETWEEN SAIDEARS; AND A PLURALITY OF NEEDLES POINTED AT BOTH ENDS MOUNTED IN ANDENCAPSULATED BY SAID APERTURES, EACH HAVING ONE END IN CONTACT WITH THECONDUCTIVE PORTION OF SAID CONDUCTOR AND ONE END PROJECTING OUTWARDLYFROM SAID APERTURE.